map -package:Cabal -package:base -package:text -package:bytestring -package:blaze-html -package:case-insensitive -package:hedgehog -package:containers -package:aeson -package:base-compat -package:regex-tdfa package:pipes is:exact

Apply a function to all values flowing downstream
map id = cat

map (g . f) = map f >-> map g